1. Field
One or more embodiments of the present invention relate to a tomography apparatus and a method for reconstructing a tomography image thereof.
2. Description of the Related Art
Medical imaging apparatuses are used to acquire an image of an internal structure of an object. Medical image apparatuses that are non-invasive testing apparatuses capture images and provide a processed image to a user including processed structural details, internal tissues, and the flow of fluids in a human body. The user who is, for example, a medical doctor, may diagnose a health state and a disease of a patient by using a medical image output from the medical image processing apparatus.
A tomography apparatus is a typical apparatus among apparatuses for capturing an image of an object by projecting X-rays toward a patient. Herein, tomography apparatus includes a computed tomography (CT) apparatus.
Of the medical image processing apparatuses, the tomography apparatus may provide a cross-sectional image of an object which clearly shows an internal structure, for example, organs such as kidneys, lungs, etc., of the object, without an overlap therebetween, contrary to a general X-ray apparatus. Accordingly, the tomography apparatus is widely used for accurate diagnosis of diseases. In the following description, a medical image acquired by the tomography apparatus is referred to as a tomography image.
In order to acquire a tomography image, a tomography scan is performed on the object by using a tomography apparatus and thus raw data is acquired. The tomography image is reconstructed by using the acquired raw data. The raw data may be projection data, which is obtained by projecting X-rays toward the object, or a sinogram that is a group of pieces of the projection data.
When an object that is a target of a tomography scan moves, motion of the object occurs during one cycle. Due to the motion of the object, motion artifacts may occur in the reconstruction of a tomography image
FIG. 2 is a view for describing motion artifacts existing in a reconstructed tomography image 200. FIG. 2 illustrates a tomography image acquired by a full reconstruction method in which an image is reconstructed by using raw data acquired when rotating around an object 210 by 360° or more.
Referring to FIG. 2, when motion artifacts are present in the reconstructed tomography image 200, an outermost edge 220 of the object 210 is unclear due to the motion artifacts. Further, an inner edge 230 of the reconstructed tomography image 200 is blurred due to the motion of the object 210.
The motion artifacts in a tomography image degrade the quality of the tomography image, and thus when a user, for example, a medical doctor, reads the tomography image and diagnoses a disease, the user is unable to accurately read the tomography image and diagnose the disease.
Thus, when a tomography scan is performed on a moving object, it is important to reconstruct a tomography image in which image blurring caused by motion artifacts is reduced.